1. Field of the Invention
The present invention generally relates to discrete inductors and more particularly to a discrete inductor comprising top and bottom lead frames, the interconnected leads of which form a coil about a closed-loop magnetic core.
2. Description of the Related Art
A review of known discrete inductors reveals a variety of structures including encapsulated wire-wound inductors having either round or flat wire wound around a magnetic core. Exemplary magnetic cores include toriodal cores, “I” style drum cores, “T” style drum cores, and “E” style drum cores. Other known structures include wire wound devices having iron powder cores and metal alloy powder cores. It is also known to form a surface mount discrete inductor employing a wire wound around a magnetic core. The fabrication of wire wound inductors is an inefficient and complex process. Open spools are typically used to facilitate the winding of the wire around the drum core. In the case of toroidal cores, the wire must be repeatedly fed through the center hole.
Non-wire wound discrete inductors include solenoid coil conductors such as disclosed in U.S. Pat. No. 6,930,584 entitled “Microminiature Power Converter” and multi-layer inductors. Exemplary multi-layer inductors are disclosed in U.S. Pat. No. 4,543,553 entitled “Chip-type Inductor”, U.S. Pat. No. 5,032,815 entitled “Lamination Type Inductor”, U.S. Pat. No. 6,630,881 entitled “Method for Producing Multi-layered Chip Inductor”, and U.S. Pat. No. 7,046,114 entitled “Laminated Inductor”. These non-wire wound discrete inductors require multiple layers and are of complex structure and not easily manufacturable.
In view of the limitations of the prior art, there remains a need in the art for a discrete power inductor that is easily manufacturable in high volume using existing techniques. There is also a need in the art for a discrete power inductor that provides a low cost discrete power inductor. There is a further need in the art for discrete power inductor that maximizes the inductance per unit area and that minimizes resistance. There is also a need in the art for a compact discrete power inductor that combines a small physical size with a minimum number of turns to provide a small footprint and thin profile.